<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>02_并集选择器</title>
    <style>
        .rich {
            color: gold;
        }
        .beauty {
            color: red;
        }
        .dog {
            color: blue;
        }
        .pig {
            color: green;
        }
        /* 选中类名为：rich或beauty或dog或pig或id为suxi的元素*/
        .rich,
        .beauty,
        .dog,
        .pig,
        #suxi {
            font-size: 40px;
            background-color: gray;
            width: 180px;
        }
    </style>
</head>
<body>
    <h2 class="rich">土豪张三</h2>
    <h2 class="beauty">明星李四</h2>
    <h2>破产王五（不加任何样式）</h2>
    <hr>
    <p class="dog">小狗旺财</p>
    <p class="pig">小猪佩奇</p>
    <p id="suxi">小羊苏西</p>
</body>
</html>